This study is an extension of the original placebo-controlled trial to determine the safety and efficacy of Copolymer I in patients with multiple sclerosis. The objectives of this trial are 1) to assess the long-term safety of Cop I in relapsing-remitting MS patients, 2) to evaluate the long-term neurologic course of the disease in patients receiving Cop I by regular neurological examinations, and 3) to evaluate the neurologic course of the disease in these patients by the clinical monitoring of exacerbations.